Proanthocyanidins battle blood vessel degradation: study

22-Dec-2008 - Last updated on 23-Dec-2008 at 11:02 GMT

New research has shown the ability of oligomeric proanthocyanidins (OPC) to protect blood vessels against degradation caused by the likes of ageing and smoking.

Ageing of the vasculature – otherwise known as senescence – has been associated with endothelial dysfunction, impaired angiogenesis and enhanced occurrence of atherosclerosis.

The researchers speculated the OPCs – being antioxidants - function by reducing DNA damage and oxidative stress.

“The results therefore provide a basis for further investigating the potential effects of this specific OPCs-compound in reducing risk of atherosclerosis and the molecular mechanisms involved,” they concluded.

Method

In the study, a proprietary blend of OPCs derived from Vitis vinifera seeds rich in specific oligomeric proanthocyanidins was found to markedly delay the onset of replicative senescence in lab-grown, human endothelial cells taken from umbilical cords.

OPC was found to effectively delay SIPS (stress induced senescence) caused by exposure to rotenone, a chemical substance that is known to generate oxidative stress.

SIPS cells were incubated with a range of rotenone (Sigma) concentrations and production was determined by dihydro-ethidium (Invitrogen), followed by examination by fluorescence microscopy and quantification of the signal by image analysis software.

The ability of OPCs to delay senescence was associated with a decrease in the levels of a marker of DNA damage and DNA terminal ends (gamma-H2AX), suggesting that the possible molecular mechanism by which OPCs delay senescence in endothelial cells is through reduction in DNA damage.

This hypothesis is supported by observations made in other research studies, showing that extent of DNA damage and levels of gamma-H2AX increase as cells progress to senescence.

Delayed endothelial cell senescence

“Atherosclerosis and the associated cardiovascular complications constitute the leading cause of death in the Western hemisphere,” said lead author, Dr Geetha Achanta.

“Smokers, hypertensives and the elderly are especially at risk. The OPCs used in this study have been shown in our previous investigations to exhibit strong antioxidant activity. The findings from the current study suggest a novel biological activity for the product: delaying endothelial cell senescence. We are currently attempting to further elucidate the mechanisms by which the product delays endothelial cell senescence, which would provide a firm basis for testing its potential application in reducing risk of cardiovascular diseases.”

The study, called “A Potential Role for Oligomeric Proanthocyanidins (OPCs) in delaying Senescence in Endothelial Cells” was presented to conference at the 15th Annual Meeting of the Society for Free Radical Biology and Medicine in Indianapolis, Indiana.

Compared to blood vessels in healthy people, blood vessels of people in the early stages of atherosclerosis or who are otherwise at risk for developing this disease, show a greater number of aged endothelial cells.

Previous studies at Utrecht University have shown OPCs significantly protect human LDL cholesterol from oxidation, supporting a potential application for this product in reducing risk of atherosclerosis.